DOCSLIB.ORG

Far-Field Impacts of Tidal Energy Extraction and Sea Level Rise in the Gulf of Maine

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Far-Field Impacts of Tidal Energy Extraction and Sea Level Rise in the Gulf of Maine University of Rhode Island DigitalCommons@URI Open Access Master's Theses 2016 Far-Field Impacts of Tidal Energy Extraction and Sea Level Rise in the Gulf of Maine Boma Kresning University of Rhode Island, [email protected] Follow this and additional works at: https://digitalcommons.uri.edu/theses Recommended Citation Kresning, Boma, "Far-Field Impacts of Tidal Energy Extraction and Sea Level Rise in the Gulf of Maine" (2016). Open Access Master's Theses. Paper 903. https://digitalcommons.uri.edu/theses/903 This Thesis is brought to you for free and open access by DigitalCommons@URI. It has been accepted for inclusion in Open Access Master's Theses by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. FAR-FIELD IMPACTS OF TIDAL ENERGY EXTRACTION AND SEA LEVEL RISE IN THE GULF OF MAINE BY BOMA KRESNING A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN OCEAN ENGINEERING UNIVERSITY OF RHODE ISLAND 2016 MASTER OF SCIENCE THESIS OF BOMA KRESNING APPROVED: Thesis Committee: Major Professor M. Reza Hashemi Jason Dahl John W. King Nasser H. Zawia DEAN OF THE GRADUATE SCHOOL UNIVERSITY OF RHODE ISLAND 2016 ABSTRACT The dynamics of tides in the Gulf of Maine are unique due to the tidal reso- nance, which generates the largest tidal range in the world (about 16 m). Conse- quently, a large tidal energy resource is available in this area, particularly in the Bay of Fundy, and is expected to be harvested in the future. Currently, more than 6 projects are operational or under development in this region (in both US and Canadian waters). Understanding the far-field impacts of tidal-stream arrays is important for future development of tidal energy extraction. The impacts include possible changes in water elevation, currents, and sediment transport. Accord- ingly, a number of previous studies have assessed the impacts of the tidal energy development in the Gulf of Maine. Further, due to the sea level rise (SLR), those impacts may also change during the project lifetime, which is usually more than 25 years. The objective of this study is to assess the combined effects of SLR and tidal energy extraction on the dynamics of tides in the Gulf of Maine. A tidal model of the Gulf of Maine was developed using Regional Ocean Model System (ROMS) at one arcminute scale. The model extends from 71.5W to 63.0W and from 39.5N to 46.0N. After validation of the model at NOAA tidal gauge stations and NERACOOS buoys, several scenarios; including SLR scenario, and tidal extraction scenario, were examined. Recent studies suggest that the global dynamics of tides will change due to SLR; therefore, SLR not only affects the bathymetry of the model inside the domain, it also changes the boundary forcing, which was considered in this effort. The results of the impacts of the tidal energy extraction with and without the SLR were presented, and compared with those from literature. Up to 4% decrease in tidal range and M2 amplitude was estimated in Minas Basin due to the 2.5 GW extraction scenario without SLR. On Massachusetts coastal area, the impacts of the same scenario can be considered negligible, 0.94%. In summary, the implementation of modified boundary forcing due to SLR, which was ignored in the previous works, can change the results of the impact assessment. Based on the results, the far-field impact is more threatening in coastal regions of US. However, the impact of energy extraction in Minas Passage is relatively small. Compared to the model validation, the impacts were inside the uncertainty level of the model. For example, maximum change in Boston coastal area was calculated up to 1.65 %, which is inside the level of uncertainty in models, about 10 %. Furthermore, the impact of SLR on the dynamics of tides is much more than energy extraction assuming 2.5 GW extraction in Minas Passage. ACKNOWLEDGMENTS First, I would like to acknowledge my Major Professor, M. Reza Hashemi for his continuous support, guidance, and help of this thesis. Also, I want to appreciate my other committee members, Jason Dahl, John King, Malcolm Spaulding and Huijie Xue for their input in my thesis. Additionally, a thank you for Matias Green and Sophie B. Williams from Bangor University, Wales for their support in global change in tidal dynamics data for this thesis. Lastly, I would like to acknowledge my colleagues in ocean engineering URI, Michael Shelby and Lauren Schambach for their assistance. Thank you for a great time in Ocean Engineering URI. iv TABLE OF CONTENTS ABSTRACT .................................. ii ACKNOWLEDGMENTS .......................... iv TABLE OF CONTENTS ..........................v LIST OF TABLES ............................... viii LIST OF FIGURES ..............................x CHAPTER 1 Introduction ...............................1 1.1 Background . .1 1.2 Area of study . .1 1.3 Literature review . .2 1.3.1 Tidal energy development . .2 1.3.2 Tidal energy resource in the Gulf of Maine . .6 1.3.3 Physical impacts of tidal energy extraction . .7 1.3.4 Sea level rise . 10 1.3.5 Introductory remarks . 12 1.4 Objectives . 14 2 Methods ................................. 16 2.1 Data . 16 2.1.1 Bathymetry . 16 2.1.2 TPXO7 . 16 v Page 2.1.3 Tidal water elevation and tidal amplitude . 16 2.1.4 Tidal current velocity data . 17 2.1.5 SLR . 17 2.2 Methodology . 18 2.3 Theoretical background . 18 2.3.1 Tidal constituents . 18 2.3.2 Resonance in a basin . 18 2.3.3 Empirical equations for vertical velocity profile . 20 2.3.4 Simulations of tidal turbine in ocean models . 20 2.4 Tidal modeling using ROMS . 22 2.4.1 ROMS theoretical background . 22 2.4.2 Bottom stress parameterization . 22 2.5 Tidal turbines simulation in ROMS model . 24 2.5.1 Increasing bottom friction to simulate energy extraction . 24 2.5.2 Actuator disc concept . 25 2.6 ROMS tidal model development . 26 2.6.1 Tidal stream resource assesment . 27 2.6.2 Impact of tidal stream turbines and SLR . 28 3 Results .................................. 29 3.1 Model validation . 29 3.1.1 Tidal amplitudes validation . 29 3.1.2 Tidal current validation . 34 3.1.3 Increased bottom drag coefficient and tidal energy ex- traction . 40 vi Page 3.2 Tidal resource assessment in the Gulf of Maine . 42 3.2.1 Present tidal energy resources in the Gulf of Maine . 43 3.2.2 Impacts of SLR on the tidal stream energy resource . 45 3.3 Impacts of energy extraction and SLR on tidal dynamics . 46 4 Discussion ................................ 56 5 Conclusion ................................ 59 LIST OF REFERENCES .......................... 61 BIBLIOGRAPHY ............................... 64 vii LIST OF TABLES Table Page 1.1 Some of the tidal barrage/lagoon projects worldwide (Multon, 2013) . .3 1.2 Some important tidal-stream projects in the world (Bahaj, 2011)3 1.3 Tidal energy sites (mostly under study) in the Gulf of Maine. .7 2.1 10 Significant Tidal Constituents . 19 2.2 List of Symbols in ROMS Formulation . 23 2.3 List of variables for turbine simulation in ROMS model. 25 3.1 Comparison of M2 constituents at 11 tidal stations . 31 3.2 Comparison of S2 constituents at 5 tidal stations . 32 3.3 Tidal ellipse parameters comparison between ROMS and ob- served data. 37 3.4 Tidal energy extraction scenario summary . 41 3.5 Power flux calculation summary at Minas Passage for 1.23 GW tidal-stream extraction scenario . 43 3.6 Summary of available maximum theoretical power at Minas Pas- sage and comparison with the previous studies. 44 3.7 Summary of available maximum theoretical power in the Gulf of Maine (see Figure 3.14 for site locations). 45 3.8 Summary of available average theoretical power and the impacts on the resources in the Gulf of Maine (see Figure 3.14 for site locations). 47 3.9 Summary of energy extraction scenarios in ROMS. 48 viii Table Page 3.10 Impact of energy extraction and SLR scenarios on the M2 am- plitude at Minas Basin and Boston. The M2 amplitudes at the present day are 5.24 m and 1.49 m for Minas Basin and Boston, respectively. 49 3.11 Impact of energy extraction and SLR scenarios on the tidal range at Minas Basin and Boston. The tidal range at the present day are 15.08 m and 4.54 m for Minas Basin and Boston, respec- tively. 50 3.12 Summary of the model validation from research related to the impacts of tidal-stream energy extraction in the Gulf of Maine. 50 5.1 Summary of the impact of energy extraction and SLR scenarios on the M2 and the tidal range. The tidal range at the present day are 15.08 m and 4.54 m for Minas Basin and Boston, respec- tively. For the M2 component, the amplitudes at the present day are 5.24 m and 1.49 m for Minas Basin and Boston, respectively. 60 ix LIST OF FIGURES Figure Page 1.1 Map of the Gulf of Maine including the bathymetry. Red stars show tidal stations for sea level data, red triangles show NER- ACOOS buoys and numbers show previously studied sites. See Table 1.3 for list of projects. .2 1.2 Illustration of stream turbine types (Khan et al., 2009). .4 1.3 Power curve for the SeaGen-S tidal stream turbine by Marine Current Turbine. .4 1.4 Illustration of tidal-stream turbine arrays (Divett et al., 2013; Chowdhury et al., 2013). .5 1.5 Optimum multiple line array configuration with recommended spacing between turbines. Colors represents generated wake from the turbines due to incoming current.
Load more

Recommended publications
  • Time and Tides in the Gulf of Maine a Dockside Dialogue Between Two Old Friends
    1 Time and Tides in the Gulf of Maine A dockside dialogue between two old friends by David A. Brooks It's impossible to visit Maine's coast and not notice the tides. The twice-daily rise and fall of sea level never fails to impress, especially downeast, toward the Canadian border, where the tidal range can exceed twenty feet. Proceeding northeastward into the Bay of Fundy, the range grows steadily larger, until at the head of the bay, "moon" tides of greater than fifty feet can leave ships wallowing in the mud, awaiting the water's return. My dockside companion, nodding impatiently, interrupts: Yes, yes, but why is this so? Why are the tides so large along the Maine coast, and why does the tidal range increase so dramatically northeastward? Well, my friend, before we address these important questions, we should review some basic facts about the tides. Here, let me sketch a few things that will remind you about our place in the sky. A quiet rumble, as if a dark cloud had suddenly passed overhead. Didn’t expect a physics lesson on this beautiful day. 2 The only physics needed, my friend, you learned as a child, so not to worry. The sketch is a top view, looking down on the earth’s north pole. You see the moon in its monthly orbit, moving in the same direction as the earth’s rotation. And while this is going on, the earth and moon together orbit the distant sun once a year, in about twelve months, right? Got it skippah.
    [Show full text]
  • Moons Phases and Tides
    Moon’s Phases and Tides Moon Phases Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area. From Earth, the lit portion we see of the moon waxes (grows) and wanes (shrinks). The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky The Moon passes through four major shapes during a cycle that repeats itself every 29.5 days. The phases always follow one another in the same order: New moon Waxing Crescent First quarter Waxing Gibbous Full moon Waning Gibbous Third (last) Quarter Waning Crescent • IF LIT FROM THE RIGHT, IT IS WAXING OR GROWING • IF DARKENING FROM THE RIGHT, IT IS WANING (SHRINKING) Tides • The Moon's gravitational pull on the Earth cause the seas and oceans to rise and fall in an endless cycle of low and high tides. • Much of the Earth's shoreline life depends on the tides. – Crabs, starfish, mussels, barnacles, etc. – Tides caused by the Moon • The Earth's tides are caused by the gravitational pull of the Moon. • The Earth bulges slightly both toward and away from the Moon. -As the Earth rotates daily, the bulges move across the Earth. • The moon pulls strongly on the water on the side of Earth closest to the moon, causing the water to bulge. • It also pulls less strongly on Earth and on the water on the far side of Earth, which results in tides. What causes tides? • Tides are the rise and fall of ocean water.
    [Show full text]
  • Tsunami, Seiches, and Tides Key Ideas Seiches
    Tsunami, Seiches, And Tides Key Ideas l The wavelengths of tsunami, seiches and tides are so great that they always behave as shallow-water waves. l Because wave speed is proportional to wavelength, these waves move rapidly through the water. l A seiche is a pendulum-like rocking of water in a basin. l Tsunami are caused by displacement of water by forces that cause earthquakes, by landslides, by eruptions or by asteroid impacts. l Tides are caused by the gravitational attraction of the sun and the moon, by inertia, and by basin resonance. 1 Seiches What are the characteristics of a seiche? Water rocking back and forth at a specific resonant frequency in a confined area is a seiche. Seiches are also called standing waves. The node is the position in a standing wave where water moves sideways, but does not rise or fall. 2 1 Seiches A seiche in Lake Geneva. The blue line represents the hypothetical whole wave of which the seiche is a part. 3 Tsunami and Seismic Sea Waves Tsunami are long-wavelength, shallow-water, progressive waves caused by the rapid displacement of ocean water. Tsunami generated by the vertical movement of earth along faults are seismic sea waves. What else can generate tsunami? llandslides licebergs falling from glaciers lvolcanic eruptions lother direct displacements of the water surface 4 2 Tsunami and Seismic Sea Waves A tsunami, which occurred in 1946, was generated by a rupture along a submerged fault. The tsunami traveled at speeds of 212 meters per second. 5 Tsunami Speed How can the speed of a tsunami be calculated? Remember, because tsunami have extremely long wavelengths, they always behave as shallow water waves.
    [Show full text]
  • Canada 21: Shepody Bay, New Brunswick
    CANADA 21: SHEPODY BAY, NEW BRUNSWICK Information Sheet on Ramsar Wetlands Effective Date of Information: The information provided is taken from text supplied at the time of designation to the List of Wetlands of International Importance, May 1987 and updated by the Canadian Wildlife Service - Atlantic Region in October 2001. Reference: 21st Ramsar site designated in Canada. Name and Address of Compiler: Canadian Wildlife Service, Environment Canada, Box 6227, 17 Waterfowl Lane, Sackville, N.B, E4L 1G6. Date of Ramsar Designation: 27 May 1987. Geographical Coordinates: 45°47'N., 64°35'W. General Location: Shepody Bay is situated at the head of the Bay of Fundy, 50 km south of the City of Moncton, New Brunswick. Area: 12 200 ha. Wetland Type (Ramsar Classification System): Marine and coastal wetlands: Type A - marine waters; Type D - rocky marine shores and offshore islands; Type F - estuarine waters; Type G -intertidal mud, sand, and salt flats; Type H - intertidal marshes. Altitude: Range is from - 6 to 6 m. Overview (Principle Characteristics): The area consists of 7700 ha of open water, 4000 ha of mud flats, 800 ha of salt marsh and 100 ha of beach. Physical Features (Geology, Geomorphology, Hydrology, Soils, Water, Climate): The area is situated at the head of the Bay of Fundy, an area with the largest tidal range in the world (up to 14 m in Shepody Bay). Shepody Bay is a large tidal embayment surrounded by low, rolling upland. A narrow band of salt marsh occurs along the western shore, whereas the eastern side is characterised by a rocky, eroding coastline with sand- gravel beaches.
    [Show full text]
  • Tidal Hydrodynamic Response to Sea Level Rise and Coastal Geomorphology in the Northern Gulf of Mexico
    University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2015 Tidal hydrodynamic response to sea level rise and coastal geomorphology in the Northern Gulf of Mexico Davina Passeri University of Central Florida Part of the Civil Engineering Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Passeri, Davina, "Tidal hydrodynamic response to sea level rise and coastal geomorphology in the Northern Gulf of Mexico" (2015). Electronic Theses and Dissertations, 2004-2019. 1429. https://stars.library.ucf.edu/etd/1429 TIDAL HYDRODYNAMIC RESPONSE TO SEA LEVEL RISE AND COASTAL GEOMORPHOLOGY IN THE NORTHERN GULF OF MEXICO by DAVINA LISA PASSERI B.S. University of Notre Dame, 2010 A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Civil, Environmental, and Construction Engineering in the College of Engineering and Computer Science at the University of Central Florida Orlando, Florida Spring Term 2015 Major Professor: Scott C. Hagen © 2015 Davina Lisa Passeri ii ABSTRACT Sea level rise (SLR) has the potential to affect coastal environments in a multitude of ways, including submergence, increased flooding, and increased shoreline erosion. Low-lying coastal environments such as the Northern Gulf of Mexico (NGOM) are particularly vulnerable to the effects of SLR, which may have serious consequences for coastal communities as well as ecologically and economically significant estuaries.
    [Show full text]
  • Tidal Resonance in the Gulf of Thailand
    Ocean Sci., 15, 321–331, 2019 https://doi.org/10.5194/os-15-321-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Tidal resonance in the Gulf of Thailand Xinmei Cui1,2, Guohong Fang1,2, and Di Wu1,2 1First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China 2Laboratory for Regional Oceanography and Numerical Modelling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China Correspondence: Guohong Fang (fanggh@fio.org.cn) Received: 12 August 2018 – Discussion started: 24 August 2018 Revised: 1 February 2019 – Accepted: 18 February 2019 – Published: 29 March 2019 Abstract. The Gulf of Thailand is dominated by diurnal 1323 m. If the GOT is excluded, the mean depth of the rest tides, which might be taken to indicate that the resonant fre- of the SCS (herein called the SCS body and abbreviated as quency of the gulf is close to one cycle per day. However, SCSB) is 1457 m. Tidal waves propagate into the SCS from when applied to the gulf, the classic quarter-wavelength res- the Pacific Ocean through the Luzon Strait (LS) and mainly onance theory fails to yield a diurnal resonant frequency. In propagate in the southwest direction towards the Karimata this study, we first perform a series of numerical experiments Strait, with two branches that propagate northwestward and showing that the gulf has a strong response near one cycle per enter the Gulf of Tonkin and the GOT. The energy fluxes day and that the resonance of the South China Sea main area through the Mindoro and Balabac straits are negligible (Fang has a critical impact on the resonance of the gulf.
    [Show full text]
  • Lady Crabs, Ovalipes Ocellatus, in the Gulf of Maine
    18_04049_CRABnotes.qxd 6/5/07 8:16 PM Page 106 Notes Lady Crabs, Ovalipes ocellatus, in the Gulf of Maine J. C. A. BURCHSTED1 and FRED BURCHSTED2 1 Department of Biology, Salem State College, Salem, Massachusetts 01970 USA 2 Research Services, Widener Library, Harvard University, Cambridge, Massachusetts 02138 USA Burchsted, J. C. A., and Fred Burchsted. 2006. Lady Crabs, Ovalipes ocellatus, in the Gulf of Maine. Canadian Field-Naturalist 120(1): 106-108. The Lady Crab (Ovalipes ocellatus), mainly found south of Cape Cod and in the southern Gulf of St. Lawrence, is reported from an ocean beach on the north shore of Massachusetts Bay (42°28'60"N, 70°46'20"W) in the Gulf of Maine. All previ- ously known Gulf of Maine populations north of Cape Cod Bay are estuarine and thought to be relicts of a continuous range during the Hypsithermal. The population reported here is likely a recent local habitat expansion. Key Words: Lady Crab, Ovalipes ocellatus, Gulf of Maine, distribution. The Lady Crab (Ovalipes ocellatus) is a common flats (Larsen and Doggett 1991). Lady Crabs were member of the sand beach fauna south of Cape Cod. not found in intensive local studies of western Cape Like many other members of the Virginian faunal Cod Bay (Davis and McGrath 1984) or Ipswich Bay province (between Cape Cod and Cape Hatteras), it (Dexter 1944). has a disjunct population in the southern Gulf of St. Berrick (1986) reports Lady Crabs as common on Lawrence (Ganong 1890). The Lady Crab is of consid- Cape Cod Bay sand flats (which commonly reach 20°C erable ecological importance as a consumer of mac- in summer).
    [Show full text]
  • Innovation Outlook: Ocean Energy Technologies, International Renewable Energy Agency, Abu Dhabi
    INNOVATION OUTLOOK OCEAN ENERGY TECHNOLOGIES A contribution to the Small Island Developing States Lighthouses Initiative 2.0 Copyright © IRENA 2020 Unless otherwise stated, material in this publication may be freely used, shared, copied, reproduced, printed and/or stored, provided that appropriate acknowledgement is given of IRENA as the source and copyright holder. Material in this publication that is attributed to third parties may be subject to separate terms of use and restrictions, and appropriate permissions from these third parties may need to be secured before any use of such material. ISBN 978-92-9260-287-1 For further information or to provide feedback, please contact IRENA at: [email protected] This report is available for download from: www.irena.org/Publications Citation: IRENA (2020), Innovation outlook: Ocean energy technologies, International Renewable Energy Agency, Abu Dhabi. About IRENA The International Renewable Energy Agency (IRENA) serves as the principal platform for international co-operation, a centre of excellence, a repository of policy, technology, resource and financial knowledge, and a driver of action on the ground to advance the transformation of the global energy system. An intergovernmental organisation established in 2011, IRENA promotes the widespread adoption and sustainable use of all forms of renewable energy, including bioenergy, geothermal, hydropower, ocean, solar and wind energy, in the pursuit of sustainable development, energy access, energy security and low-carbon economic growth and prosperity. Acknowledgements IRENA appreciates the technical review provided by: Jan Steinkohl (EC), Davide Magagna (EU JRC), Jonathan Colby (IECRE), David Hanlon, Antoinette Price (International Electrotechnical Commission), Peter Scheijgrond (MET- support BV), Rémi Gruet, Donagh Cagney, Rémi Collombet (Ocean Energy Europe), Marlène Moutel (Sabella) and Paul Komor.
    [Show full text]
  • Minas Basin, N.S
    An examination of the population characteristics, movement patterns, and recreational fishing of striped bass (Morone saxatilis) in Minas Basin, N.S. during summer 2008 Report prepared for Minas Basin Pulp and Power Co. Ltd. Contributors: Jeremy E. Broome, Anna M. Redden, Michael J. Dadswell, Don Stewart and Karen Vaudry Acadia Center for Estuarine Research Acadia University Wolfville, NS B4P 2R6 June 2009 2 Executive Summary This striped bass study was initiated because of the known presence of both Shubenacadie River origin and migrant USA striped bass in the Minas Basin, the “threatened” species COSEWIC designation, the existence of a strong recreational fishery, and the potential for impacts on the population due to the operation of in- stream tidal energy technology in the area. Striped bass were sampled from Minas Basin through angling creel census during summer 2008. In total, 574 striped bass were sampled for length, weight, scales, and tissue. In addition, 529 were tagged with individually numbered spaghetti tags. Striped bass ranged in length from 20.7-90.6cm FL, with a mean fork length of 40.5cm. Data from FL(cm) and Wt(Kg) measurements determined a weight-length relationship: LOG(Wt) = 3.30LOG(FL)-5.58. Age frequency showed a range from 1-11 years. The mean age was 4.3 years, with 75% of bass sampled being within the Age 2-4 year class. Total mortality (Z) was estimated to be 0.60. Angling effort totalling 1732 rod hours was recorded from June to October, 2008, with an average 7 anglers fishing per tide. Catch per unit effort (Fish/Rod Hour) was determined to be 0.35, with peak landing periods indicating a relationship with the lunar cycle.
    [Show full text]
  • Lecture 10: Tidal Power
    Lecture 10: Tidal Power Chris Garrett 1 Introduction The maintenance and extension of our current standard of living will require the utilization of new energy sources. The current demand for oil cannot be sustained forever, and as scientists we should always try to keep such needs in mind. Oceanographers may be able to help meet society's demand for natural resources in some way. Some suggestions include the oceans in a supportive manner. It may be possible, for example, to use tidal currents to cool nuclear plants, and a detailed knowledge of deep ocean flow structure could allow for the safe dispersion of nuclear waste. But we could also look to the ocean as a renewable energy resource. A significant amount of oceanic energy is transported to the coasts by surface waves, but about 100 km of coastline would need to be developed to produce 1000 MW, the average output of a large coal-fired or nuclear power plant. Strong offshore winds could also be used, and wind turbines have had some limited success in this area. Another option is to take advantage of the tides. Winds and solar radiation provide the dominant energy inputs to the ocean, but the tides also provide a moderately strong and coherent forcing that we may be able to effectively exploit in some way. In this section, we first consider some of the ways to extract potential energy from the tides, using barrages across estuaries or tidal locks in shoreline basins. We then provide a more detailed analysis of tidal fences, where turbines are placed in a channel with strong tidal currents, and we consider whether such a system could be a reasonable power source.
    [Show full text]
  • Hydroelectric Power -- What Is It? It=S a Form of Energy … a Renewable Resource
    INTRODUCTION Hydroelectric Power -- what is it? It=s a form of energy … a renewable resource. Hydropower provides about 96 percent of the renewable energy in the United States. Other renewable resources include geothermal, wave power, tidal power, wind power, and solar power. Hydroelectric powerplants do not use up resources to create electricity nor do they pollute the air, land, or water, as other powerplants may. Hydroelectric power has played an important part in the development of this Nation's electric power industry. Both small and large hydroelectric power developments were instrumental in the early expansion of the electric power industry. Hydroelectric power comes from flowing water … winter and spring runoff from mountain streams and clear lakes. Water, when it is falling by the force of gravity, can be used to turn turbines and generators that produce electricity. Hydroelectric power is important to our Nation. Growing populations and modern technologies require vast amounts of electricity for creating, building, and expanding. In the 1920's, hydroelectric plants supplied as much as 40 percent of the electric energy produced. Although the amount of energy produced by this means has steadily increased, the amount produced by other types of powerplants has increased at a faster rate and hydroelectric power presently supplies about 10 percent of the electrical generating capacity of the United States. Hydropower is an essential contributor in the national power grid because of its ability to respond quickly to rapidly varying loads or system disturbances, which base load plants with steam systems powered by combustion or nuclear processes cannot accommodate. Reclamation=s 58 powerplants throughout the Western United States produce an average of 42 billion kWh (kilowatt-hours) per year, enough to meet the residential needs of more than 14 million people.
    [Show full text]
  • Estuarine Tidal Response to Sea Level Rise: the Significance of Entrance Restriction
    Estuarine, Coastal and Shelf Science 244 (2020) 106941 Contents lists available at ScienceDirect Estuarine, Coastal and Shelf Science journal homepage: http://www.elsevier.com/locate/ecss Estuarine tidal response to sea level rise: The significance of entrance restriction Danial Khojasteh a,*, Steve Hottinger a,b, Stefan Felder a, Giovanni De Cesare b, Valentin Heimhuber a, David J. Hanslow c, William Glamore a a Water Research Laboratory, School of Civil and Environmental Engineering, UNSW, Sydney, NSW, Australia b Platform of Hydraulic Constructions (PL-LCH), Ecole Polytechnique F´ed´erale de Lausanne (EPFL), Lausanne, Switzerland c Science, Economics and Insights Division, Department of Planning, Industry and Environment, NSW Government, Locked Bag 1002 Dangar, NSW 2309, Australia ARTICLE INFO ABSTRACT Keywords: Estuarine environments, as dynamic low-lying transition zones between rivers and the open sea, are vulnerable Estuarine hydrodynamics to sea level rise (SLR). To evaluate the potential impacts of SLR on estuarine responses, it is necessary to examine Tidal asymmetry the altered tidal dynamics, including changes in tidal amplification, dampening, reflection (resonance), and Resonance deformation. Moving beyond commonly used static approaches, this study uses a large ensemble of idealised Idealised method estuarine hydrodynamic models to analyse changes in tidal range, tidal prism, phase lag, tidal current velocity, Ensemble modelling Cluster analysis and tidal asymmetry of restricted estuaries of varying size, entrance configuration and tidal forcing as well as three SLR scenarios. For the first time in estuarine SLR studies, data analysis and clustering approaches were employed to determine the key variables governing estuarine hydrodynamics under SLR. The results indicate that the hydrodynamics of restricted estuaries examined in this study are primarily governed by tidal forcing at the entrance and the estuarine length.
    [Show full text]